Control device



Nov. 16 1926. 1,606,746

A. H. CANDEE CONTROL DEVICE Filed Dec. 10, 1919 WITNESSES; INVENTORflammw Andrew/7. C0002? 4W BY TToNEY Patented Nov. 16, 1926.

UNITED STATES 1 PATENT OFFICE.

ANDREW H. CANDEE, 0F PITTSBURGH, PENNSYL VLANIA, ASSIGNOR T0 WESTING-HOUSE ELECTRIC &. MANUFACTURING VANIA.

COMANY, A CORPORATION OF PENNSYL- CONTROL nnv cnl Application filedDecemberIlO, 1919. Serial No. 343,986.

My invention relates to control devices More specifically stated, it isthe object,

of my invention to rovide a continuously rotatable cam of difterenttransverse crosssections for actuating a switch member into its closedor resistor-short-circuiting position, the relative periods of actuationto, or

retention in, the closed position being varied by longitudinal shiftingof the cam.

Other objectsof my invention will become evident from the followingdetailed description taken in conjunction with the accompanying drawing,wherein- Figure 1 is a diagrammatic view of a control system embodyingmy present invention; and

- Fig. 2 is a view showing another elevation of my control apparatus andcertain operating electrical connections therefor.

' Referring to the drawings, the system here shown comprises'suitablesupply-circuit conductors trolley and ground; a dynamo-electric machine,such as a car-propelling motor, having a commutator-type arnected inseries relation with the dynamo electric machine to be intermittentlyshortcircuited by a control device 3 that is operated by a smallelectric motor 4.

The control device 3 comprises a station- I ary contact tip or terminal5 that is mounted upon a support or bracket 5a, and a cooperatingmovable contact tip or terminal 6 that is secured to one end of anoscillatable arm or lever 7, the other end of the lever being biasedtoward the illustrated position by means of a helical spring 8, and thelever being pivotally mounted at an incontact members. rocker arm 10 ispivotally mounted upon termediate'point 9 upon a rocker arm or lever/10.Preferably a magnetic blowout coil of a familiar type (not shown) isprovided in'connection with the co-operating The outer end 11 of the asecond support or bracket12. A roller 13,01? the like, is pivotallymounted near 'the lowermost point of the rocker arm 10 to engage a cam14, the operating shaft 15-.

of which. is driven by a smallelectric motor 4 having a commutatontypearmature 16 and a shunt field winding 17, the degree of ,energization ofwhich may be varied by a resistor 18. I

The brackets or contact supports 5a and 12 are connected to therespective terminals of the accelerating resistor 2 by conductors 19 and20, y

In addition to the rotative movement of the cam 14 that may be producedthrough theagency of the electric motor 4, the cam is'adapted forbodilylongitudinal shifting or actuation and this result may be accomplished,as -illustrated in Fig. 2, by means of an actuating coil 21 whichencloses a portion of a sleeve 22 that is rigidly secured to the cambody 14 and is adapted to loosely slidealong the cam shaft 15, althoughthe rotative movement of the cam with the shaft is insured by theprovision of a key 23 that is inserted in the shaft. For the purpose ofenergizing the actuat- 1ng coil 21, a battery 24 may be connected incircuit with the coil through a'hand-operated switch 25, which alsocloses the circuit of the auxiliary motor 4- through the battery. Toprevent too rapid longitudinal actuation of the cam 14, a dash-pot 26 issuitably connected with the s'lidable sleeve 22, whereby a relativelyslow longitudinal movement of the cam 14 and, therefore, a desirablysmooth acceleration of the main motor is insured. Return movement of thecam 14 to the illustrated normal position is ensured by a biasing spring27.

As indicated by the various section lines AA to EE, inclusive, thecontour of the cam 14 gradually increases in size from one end to theother of the cam, a comparatively sharp point or narrow ridge 14aextending to the peripheral bounding line of the cam at one end thereof,while this ridge gradually increases in size or, in other words,

therefore, the rocker arm occupies its lowermost position correspondingto the full I open position of the movable contact tip 6.

Upon rotative movement of the cam 14, the roller 13 will ride along theperiphery thereof and,'when the ridge 14a passes under the roller 13', acontact of short duration will be effected between the stationary andmovable contact tips 5 and 6, respectively. A continuous rotation of thecam 14 by the electrioinotor Will effect. periodical shortcircuits ofthe accelerating resistor 2, of short duration, so that the effect of acomparatively great resistance is produced in the circuit of the main orcar-propelling motor.

By longitudinally shifting the cam 14 towards its positions of greatencross-section, the duration of the individual short-circuits, whichcontinue to occur periodically, is gradually increased until, when theother end of the cam 14 en ages the roller 13, a permanent short-circuitof the resistor 2 is produced. In other words, by continuously rotatingthe cam 14 and shifting it longitudlnally during such rotative movement,the

effective or active circuit value of the accelcrating resistor 2 isgradually-decreased to substantially zero, and thus a smoothacceleration of the main motor may be automatically effected withoutrequiring the use of current relays or the likef The operation of mysystem and apparatus may beset forth as follows. roller 13 occupying itsnormal position at the end of the cam 14 of smaller cross-section, asindicated in solid lines in Fig. 2, the switch 25 may be closed toconcurrently energize the auxiliary motor 4 and the actuat ng coil 21.In this way, the movable contact tip 6 is intermittently brought intoengagement with the stationary contact tip 5, as previously'described,by. reasonof the rotative movement that is imparted to the cam 1&1 bythe auxiliarymotor 4, while the energization' of the actuating coil 21serves to effect a longitudinal shifting of the cam 14 towards theposition wherein the greatest transverse cross-section thereof isbrought into engagement with the roller 13. Consequently, the durationof the individual With the I tioned, or of sufficient inductivecharacteristics in the motors and other circuits, will serve'to smoothout the pulsations.

It will be appreciated that other means of providing simultaneousmovements of translation and rotation, such as the screwthreaded shaftand traveling nut that is used in limit switches for elevator control,may

be employed, if desired. Consequently, I do not wish to be restricted tothe specific circuit connections, structural details or arrangement ofparts herein set forth, as various modifications thereof may be madewithoutdeparting from the spirit and scope of my invention. I desire,therefore, that only such limitations shall be imposed as are in dicatcdin the appended claims.

I claim as my invention:

1. A control system comprising a movable switch member, a resistoradapted to be short-circuited by said switch member, an axially taperingcam for actuating said member, and electrical means for concurrentlyrotating and longitudinally shifting said cam.

2. In a system "of acceleration, the combination with an electricmotorand a resistor, of electrically controlled cam means forintermittently modifying the circuit connections of said resistor andfor varying the periods of intermittence.

3. In a system of acceleration, the combination with an electric motor asource of energy and a resistor, of continuously rotatable means forperiodically shunting said resister and means electrically governed bysaid source for varying thetime between such shunting actions.

In testimony whereof, I have hereunto AN RE 'H. oiii innn

